Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

How to Register on LPF | LPF Donations

Laser/Water.....need advice please.

N

New Guy

0
Joined
May 3, 2010
Messages
9
Points
0
I'm new, what kind of laser reflects off water best? I am trying to reflect( not refract) one off water and detect the reflection. There is more to it, but that is the main question.
 





Your question is very ... unlogical.

"In what mirror would I see myself best?" <- just about the same.

Any laser will reflect of any reflective surface obviously.
Depending on what you application requires, you should have two primary choices,
Red laser would be best if there is very long range needed as reddies have lowest divergence,
Green laser would be best for visibility if that is what's needed, but they will diverge more and maybe some small sensors will be useless at longer ranges.

If you post your question correctly, then it will be answered appropriately ;)
 
daguin said:
Uh Oh! You are starting to really sound like a vet now ;)

Peace,
dave
Click to expand...
I hang around you a lot, Professor ;)

I never get tired of reading your posts. They are almost poetically written.
Joy to read.

Naturally, I started writing in the same manner.

But let's get back to the thread and wait for the OP to explain more throughly what purpose will his laser serve.
Reflection of water surface could range from simple joy-to-observe reflection effect, to measuring tiny water movement and calculation of complex processes I don't even know about. :D

In any case, I think that red direct diode system will do, lowest price per milliwatt and focusability/divergence fits most needs.

But he needs to tell us that himself.
 
Eudaimonium said:
Your question is very ... unlogical.

"In what mirror would I see myself best?" <- just about the same.

Any laser will reflect of any reflective surface obviously.
Depending on what you application requires, you should have two primary choices,
Red laser would be best if there is very long range needed as reddies have lowest divergence,

Green laser would be best for visibility if that is what's needed, but they will diverge more and maybe some small sensors will be useless at longer ranges.

If you post your question correctly, then it will be answered appropriately ;)
Click to expand...

Diode lasers tend to have the best divergence, not just red lasers. A blu-ray or single-mode IR diode will have the exact same divergence potential as a red diode. I say potential because how much divergence the laser has depends on your optics and how well you adjust them. Their usefulness in this application depends on the type of sensor used and it's sensitivity to the wavelength in question. An invisible IR laser could work very well if an IR sensor is used. You are correct in that a single-mode diode laser would be best if low divergence is required.



5chars
 
Last edited:
ElektroFreak said:
5chars
Click to expand...
Oh, thanks for adding that dude, although you could have placed the orange part below the quote of my post, not in it.

People reading the thread might get confused.

But you are apsolutely right.
IR would also work as well, even cheaper than red per mW, However blurays would be very expensive for that matter.

But, I stand corrected :beer:
 
^Really you've never seen anyone quote like that before? It's not exactly uncommon.. Changed it.
 
Last edited:
Ok, like I said, im new to this whole thing. From what I understand different lasers are used differently. I need to shoot a beam at a liquid and have it return back to measure the distance. I dont care if its seen or not.
 
Last edited:
As long as your detector is sensitive enough, any laser will work. Since the surface of water isn't perfectly reflective, most of your power will continue past the surface and be absorbed so you'll want to use a fairly powerful laser. The small amount that is reflected is what you'll be detecting. Divergence is irrelevant unless the water is perfectly smooth, and I mean perfectly. Any disturbance at all and the laser beam will lose all collimation and become random in terms of power distribution and direction..
 
Take a large angle of incidence, this will increase the reflection. The reflection is then also polarisation dependent. The reflection at normal incidence will be relatively small.
 
Im not sure about all the fun involved with Divergence, but yea the angle would be 90 degrees and the liquid would not be completely still, although atmospheric so not mush movement there. I would love to use Infrared, sonar, or radar, but from what I understand you cant focus them into a beam. They spread into a cone and thats no good for me.
 
Ok so strong laser and sensitive reflector/sensor? Anyone have a product to suggest to look at for starters??? And when you say strong laser you mean as in green or blue?
 
You must log in or register to reply here.


Back
Top